Lecture 24: Microbial Processes Flashcards
What is a biofilm?
A thin coating of bacteria, algae or fungi on a solid surface submerged
What do Extracellular Polysaccharides allow for?
Bacteria to stick to the surface of a submerged solid
What is the difference between a biofilm and a microbial mat?
A biofilm is usually a thin layer made of only one type of species whereas a mat is usually much thicker
Where do we usually find microbial mats?
Places that are too extreme for other forms of life like hot springs or salty places because they don’t get eaten
What is a Stromatolite?
When Microbial Mats get fossilized
What makes Stromatolites reactive?
They’re small so they have a large surface area and they produce EPS
What part of the Cell makes microbes sticky and reactive?
The EPS
What is meant by microbes being reactive?
The carboxyl groups on them deprotonate giving them a net negative charge allowing positive ions to stick to it
What is the Bioremediation industry based on?
The idea that microbes are reactive
What is Biosorption?
The process whereby microbial biomass acts as a surface upon which toxic metals and radionuclides are passively absorbed and/or complexed
What is Bioaccumulation?
The metabolic processes used by living biomass in which physiologically important metal ions are absorbed by cells
What are the features of microbes that make them good for bioremediation?
Large surface area, everywhere, super reactive
What is Biomineralization?
When microorganisms grow minerals
What are the two types of Biomineralization?
Biologically induced biomineralization and Biologically controlled biomineralization
What are the characteristics of Biologically Induced Biomineralization?
There is no regulatory control and the biominerals form as incidental by-products due to the activity of the microorganisms and their surrounding environment
What are the characteristics of Biologically controlled biomineralization?
Precipitation of minerals is controlled
What are the two steps in Induced Biomineralization?
- A metal binds to the surface of the microorganism
2. The metal reacts to form anions in the solution to form biominerals
What is the mineral in induced biomineralization dependant on?
The available anions and the chemical composition of the water in which they grow
What is an example of Induced Biomineralization?
Silica in the hot springs. Because the hot springs are so rich with silica, microorganisms get covered in the silica precipitates
What is a Diatom?
A small organism that form really elaborate shells
What are shells of Diatoms made of?
Silica
What is an example of Controlled Biomineralization?
Diatoms forming their shells
What is the main idea surround Diatoms and controlled mineralization?
The diatoms use a lot of energy to pump silica in and it wants the silica so it goes out of its way to get it making it a controlled process
What is the largest fraction of Biologically controlled minerals?
Calcium carbonate that results from microorganisms that remove calcium carbonate (calcite) from the sea water to form their skeletons
What is the most important role of microbes in terms of chemical weathering?
Forming carbon dioxide via aerobic respiration or dead organic material. The CO2 that is produces reacts with water to form carbonic acid which dissolve rock
What occurs in acid mine drainage?
Sulfur and Iron in pyrite is oxidized at earths surface
What is the reaction for Pyrite oxidation?
FeS2 + 3.75O2 + 3.5H2O ➡️ Fe(OH)3 + 2H2SO4
What is Bioleeching?
Using bacteria to leech metals such as copper, zinc, uranium, nickel and cobalt from a sulfide mineral
